Bed balance

ABSTRACT

The invention relates to a bed scale with a plurality of measuring feet which each support one leg of the bed and are provided with a force transducer which delivers a signal representing a weight force acting on the measuring foot and furthermore with an evaluation device which is connected to the transmission devices in the measuring feet for receiving the signal in order to deliver a result dependent on the weight force bearing thereon. In order to improve the ease of handling and the user-friendliness it is provided according to the invention that each measuring foot has an angle lever arrangement displaceable on the floor on sliding elements, preferably rollers ( 5 ), which swivellably bears at a shorter lever arm ( 8 ) a rocker ( 1 ) which can be pushed laterally onto the leg of the bed standing on the floor to accommodate it, the suspension mounting of the rocker ( 1 ) at the shorter lever arm ( 8 ) and the longer activating lever ( 2 ) of the angle lever arrangement being arranged such that, upon the pressing down of the activating lever ( 2 ), the rocker ( 1 ) is lifted and its suspension mounting ( 9 ) is moved beyond the dead centre in which the suspension mounting ( 9 ) of the rocker ( 1 ) lies vertically above the sliding elements ( 5 ) of the angle lever arrangement. As a result the bed can, by simple working of the activating lever, be brought into the lifted position for measurement on the measuring feet.

This application is the US national phase of international applicationPCT/EP00/08665 filed Sep. 5, 2000, which designated the US.

The invention relates to a bed scale for the medical field, with whichbeds can be weighed.

Such bed scales have as a rule four measuring feet each of which cansupport one leg of the bed, in particular for example a bed roller of amovable bed, and is provided with a force transducer or sensor. Theforce transducer, for example a weighing cell, delivers a signal whichrepresents the weight force acting on the measuring foot. The measuringfeet have transmission devices for signal transmission to an evaluationdevice which receives and evaluates their signals. In many cases theevaluation device is designed as a reading and operating device whichreceives the signals of the measuring feet and is thus prepared todeliver a reading which depends on the weight force bearing on themeasuring feet. The reading and operating device can be prepared forexample such that the weight of the bed can be subtracted and then onlythe weight of the patient is displayed.

Such bed scales are known for example from DE 72 25 247 U1. The bedscale has four measuring feet each with a receiving means adapted to theouter shape of a bed roller. In order to employ and use the bed scalethe bed is lifted and one measuring foot is placed under each bed rollerand the bed is then lowered onto the measuring feet. For this purposeeither the bed has to be lifted as a whole, which requires an expensivelifting device, or it has to be lifted firstly at one end and themeasuring feet placed under the bed rollers at this end and then liftedat the opposite end and the measuring feet placed under the remainingbed rollers. With both alternatives the placing of the bed on themeasuring feet of the bed scales is very laborious and time-consumingfor the staff. The same difficulties result for beds without bedrollers, which likewise have to be lifted in order to be placed on themeasuring feet.

With other bed scales the measuring feet are each provided with a ramponto which the bed rollers can be pushed. Firstly the bed is pushed suchthat all four bed rollers are swivelled into a straight positionsuitable for pushing-on. The ramps of the measuring feet then have to bepositioned at the bed rollers and then the bed is pushed over the rampssimultaneously onto the four measuring feet. Expenditure of aconsiderable force may be required to push the bed onto the measuringfeet. Furthermore the measuring feet may slip during the pushing-on orone of the bed rollers swivel, which makes the repetition of the entireprocess necessary.

The known bed scales thus have the disadvantage that the placing of thelegs of the bed onto the measuring feet is associated with considerabledifficulties. Furthermore, the possible difficulties which may occurwhile placing the bed onto the measuring feet are such that, generally,it is not possible for a patient to be in it. Furthermore, if themeasuring feet are not wholly precisely positioned, and they do notcorrespond wholly precisely to the position of the four legs or the bedrollers at the legs, lateral forces may act on the measuring feet whenthe bed is placed onto the measuring feet. Such lateral forces canaffect the measurements of the force transducer and thus distort theresults delivered by the bed scale.

It is the object of the present invention to produce bed scales whichare easy to handle and measure precisely.

The characterizing features of patent claim 1 in conjunction with itspreamble serve to achieve this object. Advantageous embodiments of theinvention are stated in the dependent claims.

According to the present invention each measuring foot is designed as akind of angle lever which can be moved along the floor on slidingelements, preferably rollers. A rocker is swivellably attached to theshorter lever arm and is adapted to be able to be pushed laterally ontoa leg of the bed standing on the floor to engage it. The rocker can bedesigned for example such that it can be pushed laterally onto a bedroller of the leg to accomodate it for lifting while the bed roller isresting on the floor. In order to push the rocker onto the leg the anglelever arrangement is pushed forward on its sliding elements onto the leguntil the rocker engages in form-locking manner at parts of the leg, inorder to lift same. The rocker can for example be designed such that itcan be pushed onto a bed roller at the bottom end of the leg standing onthe floor, and that it, in its pushed-on state, encompasses parts of thelower hemisphere of the bed roller such that the latter can be lifted bythe rocker. The suspension mounting of the rocker on the shorter leverarm and the longer activating lever of the angle lever arrangement andits sliding elements are arranged such that, when the activating leveris pressed down, the rocker is lifted by the shorter lever arm and itssuspension mounting moved out over the dead centre, in which thesuspension mounting of the rocker lies vertically above the slidingelements of the angle lever arrangement. In this way, the angle leverarrangement with lifted rocker reaches a stable position beyond the deadcentre, in which the leg of the bed is supported by the rocker alone. Inthe stable end-position the angle lever arrangement rests on the floorwith at least one further point beside the slide elements, such that asecure position of the measuring foot is achieved. A force transducer,for example a weighing cell, is provided in each measuring foot, whichdelivers a signal from which a measurement for the weight force actingon the rocker can be determined. The signals of the force transducer aretransmitted to the evaluation device via transmission devices eitherwith cables or without wires.

As the activating lever can be designed clearly longer than the shorterlever arm, the activation of the angle lever arrangement for lifting thebed rollers is possible for the staff with little expenditure of force.

Furthermore, incorrect positioning of the legs on the measuring feetcannot occur, as the rocker can be pushed laterally onto a leg of thebed while the leg is standing on the floor, to be able to grip this legto lift it. Because the sliding elements of the measuring foot moveunder the leg of the bed during the lifting process, lateral forcescannot develop, as the measuring feet are movable in cross directionduring the lifting process.

In principle the bed scales can be used for all types of beds, includingsimple beds which have their legs standing on the floor without bedrollers. Many beds in the medical field are provided with bed rollers ontheir legs such that they are movable. It is preferred for these bedsthat the measuring feet are designed such that they can accommodate thebed rollers. It is not necessary with the present bed scales that allbed rollers are firstly aligned in a uniform direction, as the measuringfeet can also be pushed onto slanted or inclined bed rollers.

With the bed scales according to the invention the placing of the bedonto the measuring feet is made considerably easier and also requires nofurther lifting devices. The ease of handling and user-friendliness ofthe bed scales are considerably improved thereby.

The measuring feet can be placed in succession at the four bed rollersand lifted. The activation force for each lever process is small due tothe length of the activating lever. The bed scales can therefore beinstalled by all nursing staff. Furthermore, when lifting the bed, itneeds to be lifted only slightly such that the rocker comes away fromthe floor; with such a slight lifting a patient can also be in the bedduring the lifting. Furthermore no moving of the bed is necessary withthe scales according to the invention. In addition the bed rollers donot need to be set in a uniform direction beforehand, as each measuringfoot can also be pushed onto a bed roller which is inclined and this canthen be lifted.

The invention is described in the following using an embodiment in thedrawings, in which:

FIG. 1 shows a schematic perspective representation of a measuring footfor bed scales of the present invention;

FIGS. 2-4 show lateral views of successive positions of the lower partof the angle lever arrangement of a measuring foot when lifting a bed;

FIG. 5 shows a schematic perspective representation of the measuringfoot from FIG. 1 in the lifted position and with folded activatinglever.

FIG. 1 shows a schematic representation of a measuring foot. Themeasuring foot has an angle lever arrangement which has shorter leverarms 8 and an activating lever 2, which is extended via frame parts 4which carry rollers 5 at their lower ends. A suspension mounting 9 for arocker 1 is provided on the shorter lever arms 8 at their ends which areremote from the activating lever 2. The rocker 1 has two wedge-shapedsupports which are arranged opposite each other and at a distance fromeach other such that the wedge-shaped supports can be pushed under lowerperipheral areas of a bed roller standing on the floor in order toaccommodate this. The wedge-shaped supports of the rocker 1 areconnected to each other via a common back wall. As an alternative to thewedge-shaped supports, for example mandrels or rods can also be used assupports. The rocker 1 is swivellable in the suspension mounting 9against the shorter lever arm 8.

The arrangement of the suspension mounting 9 of the rocker 1 on theshorter lever arm 8 and the positions of the rollers 5 of the anglelever arrangement are designed such that, when the activating lever 2swivells out of an upright or inclined position relative to the floor,the suspension mounting of the rocker 1 on the shorter lever arms 8moves over the dead centre, in which the suspension mounting 9 of therocker lies vertically above the rollers 5 of the angle leverarrangement.

This swivel motion for lifting the rocker 1 is schematically shown inFIGS. 2 to 4 in successive positions. In FIG. 2 the rocker 1 is pushedlaterally onto a bed roller (not shown) such that it partly encompassesthis in its lower peripheral areas. Then the activating lever 2 (notshown in FIGS. 2 to 4) is swivelled towards the floor such that theframe part 4 is correspondingly swivelled, whereby the frame parts 4then move forward on the rollers 5 and then, in the position shown inFIG. 3, reach a position in which they lie vertically precisely underthe suspension mounting 9 of the rocker 1 on the shorter lever arms 8.In this position the weight force acting on the rocker no longer causestorque or angular momentum on the activating lever. If the activatinglever is swivelled out beyond this dead centre, the measuring footreaches the stable end position represented in FIG. 4 in which it lieson the one hand on the rollers 5 and on the other hand on a furtherbearing point, stable on the floor. The stability of the positiondepends on how far the suspension mounting 9 of the rocker 1 is movedout beyond the dead centre if the second bearing point comes to rest onthe floor. The arrangement should be designed such that the dead centreis exceeded by a sufficient angular amount such that the activatinglever 2 cannot be lifted unintentionally as a result of careless contactwhich, as a result, would cause a movement back into the startingposition with the bed roller on the floor.

The measuring foot represented in FIG. 1 has two frame parts 4, whichare provided with rollers 5 at their lower ends. The frame parts 4 areconnected at their upper ends by a frame crossbar 6 onto which theweighing cell (not shown) is screwed. A bridge part 3 is in turn screwedonto the weighing cell, one of the shorter lever arms 8 being attachedonto each end of the bridge part 3.

One of the frame parts 4 is provided with an activating lever 2 whichpractically represents an extension of the frame part. The activatinglever 2 is attached to the frame part 4 so that it can be pivoted withrespect to the frame part in a plane perpendicular to its actualactivation direction, such that it can be folded after the lifting ofthe measuring foot, as represented in FIG. 5, such that the projectingactivating lever 2 presents no danger to the staff.

Also provided in the measuring foot is the weighing cell which picks-upa signal which represents the weight force acting on the rocker 1. Theweighing cell can be arranged for example between the bridge part 3 andthe frame crossbar 6 and thus deliver a measurement for the weight forcebearing on the rocker 1.

In order to use the bed scale each measuring foot is pushed against abed roller by advancing the activating lever 2 on the rollers 5 suchthat each rocker 1 accommodates a bed roller. By pressing down of theactivating lever 2 the rollers 5 are pushed towards and underneath therocker 1, and the rocker 1 lifted thereby with the bed roller. When therollers 5 are moved out over the dead centre in which the rollers 5 lievertically exactly below the force-initiation point or below thesuspension mounting 9 of the rocker 1, the weight presses on themeasuring foot into the stable end-position or measuring position on thefloor (see FIG. 4).

What is claimed is:
 1. Bed scale having a plurality of measuring feeteach of which can support one leg of the bed and is provided with forcetransducer which delivers a signal representing the weight force actingon the measuring foot, and an evaluation device which is connected totransmission devices in the measuring feet for receiving up the signalsand is prepared to deliver based on the signals and is prepared todeliver based on the signals of the measuring feet a result dependent onthe weight force bearing thereon, characterized in that each measuringfoot has an angle lever arrangement displaceable on the floor on slidingelements (5), which swivellably bears at a shorter lever arm (8) arocker (1) which can be pushed laterally onto a leg of the bed standingon the floor to engage it, the angle lever arrangement and thesuspension mounting of the rocker (1) being arranged such that, uponpressing-down of the activating lever (2), the rocker (1) is lifted andits suspension mounting (9) can be moved out beyond the dead centre inwhich the suspension mounting (9) of the rocker (1) lies vertical abovethe sliding elements (5) of the angle lever arrangement.
 2. Bed scaleaccording to claim 1, characterized in that the sliding elements of theangle lever arrangement are formed by rollers (5).
 3. Bed scaleaccording to claim 1, characterized in that the rocker is shaped suchthat it can be laterally pushed onto a bed roller standing on the floorto accomodate it.
 4. Bed scale according to claim 3, characterized inthat the rocker (1) of each measuring foot has two opposing wedge-shapedsupports which are held at a distance from each other such that therocker with the two wedge-shaped supports can be pushed under a bedroller standing on the floor and in the process the wedge-shapedsupports encompass parts of the circumference of the bed roller fromunderneath.
 5. Bed scale according to claim 1, characterized in that theforce transducer of each measuring foot is formed by a weighing cellwhich senses the pressure caused by the weight on the rocker (1) on theshorter lever arm (8).
 6. Bed scale according to claim 2, characterizedin that the rollers of the angle lever arrangement are located at adistance from each other and leave free between each other space whichis so great that the rocker can swivel between the rollers of the anglelever arrangement.
 7. Bed scale according to claim 6, characterized inthat the angle lever arrangement of each measuring foot has two frameparts (4) lying at a distance form each other each of which supports atthe lower ends a roller (5), a frame cross bar 96) connecting the frameparts (4) at their opposite end, two shorter lever arms (8), which areconnected to a bridge part (3) at its opposite ends and, at their endsfacing away from the bridge part (3), bear the rocker (1) in thesuspension mounting (9), and an activating lever (2) extending from atleast one of the frame parts (4), the bridge part (3) being connectedvia a force transducer to the frame crossbar (6).
 8. Bed scale accordingto claim 1, characterized in that the activating lever is foldable in adirection perpendicular to its activation plane.